This invention relates to the field of radiation curable compositions comprising ethylenically unsaturated monomers and/or oligomers.
Radiation curable compositions have well established utility in many applications, for example coatings, inks, adhesives, and electronic applications. Acrylic monomers and/or oligomers are commonly used for such compositions because they offer an attractive cost/performance balance for radiation curable applications. In such compositions (meth)acrylic monomers are used to reduce the viscosity of the radiation curable composition to an appropriate level for application to the substrate. In some cases where application of the radiation curable composition is done by spraying or jetting techniques that require very low viscosities, high levels of (meth)acrylic monomers are needed. High monomer levels can lead to poor cured film performance as well as cause emission of objectionable odors and problems with skin irritation. In such cases it would be desirable to heat the radiation curable composition to reduce its viscosity, but this can often lead to premature gellation because of the poor thermal stability of such compositions. In certain applications, for example radiation curable ink jet compositions, the state of the art radiation curable compositions suffer from instability at high temperatures. It is an object of the present invention to improve on the high temperature stability of radiation curable compositions comprising ethylenically unsaturated monomers and/or oligomers.